Negative active material and lithium battery containing the negative active material

Abstract

A negative active material and a lithium battery including the same are disclosed. The negative active material includes a primary particle including a silicon nanowire formed on a non-carbonaceous conductive core to increase the capacity and cycle lifespan properties of the lithium battery.

What is claimed is: 
     
         1 . A negative active material comprising a primary particle, wherein the primary particle comprises:
 a non-carbonaceous conductive core; and   a silicon-based nanowire disposed on the non-carbonaceous conductive core.   
     
     
         2 . The negative active material of  claim 1 , wherein the non-carbonaceous conductive core comprises at least one selected from copper (Cu), nickel (Ni), cobalt (Co), iron (Fe), manganese (Mn), molybdenum (Mo), titanium (Ti), silicon (Si), and an alloy thereof. 
     
     
         3 . The negative active material of  claim 1 , wherein the non-carbonaceous conductive core has a spherical powder form. 
     
     
         4 . The negative active material of  claim 1 , wherein an average diameter of the non-carbonaceous conductive core is in the range of about 1 μm to about 30 μm. 
     
     
         5 . The negative active material of  claim 1 , wherein;
 the silicon-based nanowire comprises at least one selected from Si, SiOx (0<x<2), Si—Z alloys (where Z is alkali metal, alkaline earth metal, a Group 11 element, a Group 12 element, a Group 13 element, a Group 14 element, a Group 15 element, a Group 16 element, a transition metal, a rare earth element, or a combination thereof, and is not Si), or a combination thereof.   
     
     
         6 . The negative active material of  claim 1 , wherein the silicon-based nanowire is a silicon nanowire. 
     
     
         7 . The negative active material of  claim 1 , wherein the silicon-based nanowire has a diameter in the range of about 10 nm to about 500 nm, and a length in the range of about 0.1 μm to about 100 μm. 
     
     
         8 . The negative active material of  claim 1 , wherein the silicon-based nanowire is directly grown on the non-carbonaceous conductive core. 
     
     
         9 . The negative active material of  claim 8 , wherein the silicon-based nanowire is grown in the presence of at least one metal catalyst selected from the group consisting of platinum (Pt), iron (Fe), nickel (Ni), cobalt (Co), gold (Au), silver (Ag), copper (Cu), zinc (Zn), cadmium (Cd), and any combinations thereof. 
     
     
         10 . The negative active material of  claim 1 , wherein the amount of the non-carbonaceous conductive core is about 60 wt % to about 99 wt % and the amount of the silicon-based nanowire is about 1 wt % to about 40 wt %, based on the amount of the primary particle. 
     
     
         11 . The negative active material of  claim 1 , wherein the primary particle further comprises an amorphous carbonaceous coating layer, and wherein the amorphous carbonaceous coating layer is coated on at least a portion of the primary particle, such that at least a portion of the silicon-based nanowire is not exposed. 
     
     
         12 . The negative active material of  claim 11 , wherein at least about 50 volume % of the silicon-based nanowire is buried in the amorphous carbonaceous coating layer. 
     
     
         13 . The negative active material of  claim 11 , wherein the thickness of the amorphous carbonaceous coating layer is in the range of about 0.1 μm to about 10 μm. 
     
     
         14 . The negative active material of  claim 11 , wherein the amorphous carbonaceous coating layer comprises amorphous carbon selected from the group consisting of soft carbon, hard carbon, mesophase pitch carbide, calcined coke, and a combination thereof. 
     
     
         15 . The negative active material of  claim 11 , wherein the amount of the amorphous carbonaceous coating layer is in the range of about 0.1 wt % to about 30 wt %, based on the amount of the primary particle. 
     
     
         16 . The negative active material of  claim 1 , wherein the negative active material further comprises at least one carbon-based particle of natural graphite, synthetic graphite, expandable graphite, graphene, carbon black, fullerene soot, carbon nanotubes, carbon fibers, and a combination thereof. 
     
     
         17 . The negative active material of  claim 16 , wherein the carbon-based particle has a spherical form, a flat form, a fiber form, a tube form, or a powder form. 
     
     
         18 . A lithium battery comprising:
 a negative electrode comprising the negative active material according to  claim 1 ;   a positive electrode comprising a positive active material, which is disposed opposite to the negative electrode; and   an electrolyte disposed between the negative electrode and the positive electrode.   
     
     
         19 . The lithium battery of  claim 18 , wherein the negative electrode further comprises at least one binder selected from the group consisting of polyvinylidene fluoride, polyvinylidene chloride, polybenzimidazole, polyimide, polyvinyl acetate, polyacrylonitrile, polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, polyethylene, polypropylene, polystyrene, polymethylmethacrylate, polyaniline, acrylonitrile butadiene styrene, a phenol resin, an epoxy resin, polyethylene terephthalate, polytetrafluoroethylene, polyphenylene sulfide, polyamide imide, polyether imide, polyethylene sulfone, polyamide, polyacetal, polyphenylene oxide, polybutylene terephthalate, ethylene-propylene-diene terpolymer (EPDM), sulfonated ethylene-propylene-diene terpolymer, styrene butadiene rubber, fluoride rubber, and a combination thereof. 
     
     
         20 . The lithium battery of  claim 18 , wherein the negative electrode comprises at least one conductive agent selected from the group consisting of carbon black, acetylene black, Ketjen black, carbon fiber, copper, nickel, aluminum, silver, conductive polymer, and a combination thereof.